The victims, aged 16 to 44, were methodically shot in the head while sleeping at four residences, including a mother with a 4-day-old infant lying beside her, authorities said. The newborn, along with a 6-month-old and a 3-year-old, survived. The official said the killings happened before dawn.

“This was a preplanned execution of eight individuals,” state Attorney General Mike DeWine said. “It was a sophisticated operation and those who carried it out were trying to do everything they could do…